Process for manufacturing soap



Nov. 6 1923. 1,473,396

J. w. BODMAN PROCESS FOR MANUFACTURING SOAP Filed Jan. 20. 1921 Patented Nov. 6, 1923.

Mrs!) STATES JOHN W. BOIDHAN, OF WESTERN SPBINGS ILLINOIS, ASSIG-NOR TO WILLIAM GAB- RIG'UE & COMPANY, INC., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

PROCESS FOR MANUFACTURING SOAP.-

Application filed January 20, 1921. Serial No. 488,541.

To all wlwmz't concern:

Be it known that I, JOHN W. BODMAN, a citizen of the United States, 'residing at Western Springs, in the county of Cook and 6 State of Illinois, have made certain new and useful Improvements in Processes for Manufacturing Soap, of which the following is a specification.

My invention relates to a novelprocess to for manufacturing soap whereby soap may be manufactured effectively and simply with a considerable economy of time, labor, equipment and steam consumption, as well as with the realization of other economies.

I obtain the beneficial results referred to, briefly, by first mixing the soap stock with a percentage of caustic alkali solution which is less than the amount which would be re uiredto completely neutralize all of the so atty acid of the soap stock. The mass is then thoroughly emulsified, after which the saponification is completed by hydrolysis under pressure in an autoclave, the remainder of the fat being split by this process. The amount of soap formed by the percentage of caustic alkali solution used seems to act as-a catalyst during this action. The glycerol which has been split ofi from the glycerides is then separated out by settling, after which a further amount of caustic alkali solution is added, this being an amount calculated as suflicient to neutralize the remaining free fatty acid. Thereafter the manufacture of the soap may be completed, as by boiling the same in a kettle and settling.

It will be noted that the above process differs from the soap making processes in common use in that a part only of the caustic so alkali solution is first mixed with the glycerides, and an emulsion formed, comprising an incomplete soap, water, glycerine and unsaponified fats, which will have a specific gravity sufficiently different from that of as the glycerine liquors to permit the separation of the glycerine liquors by settling. In determining the amount of caustic alkali solution to be used at the beginning, two factors are to be considered. If the fatty so acids are completely neutralized there will be no settlin out of the glycerine liquors because of d' erence in specific gravity, unless a sufiicient proportion of an electrolyte, viz, common salt, is added. Accordingly,

the degree of neutralization of the fatty acids in the initial step of the process should not be sufliciently high to prevent the separation of the glycerine liquors by diiference in the specific gravity of the emulsion and the glycerine liquors. On the other hand, it is desirable to obtain as high a degree of neutralization of the fatty acids as is possible, while preserving the necessary difference in specific gravities of the emulsion and the glycerine liquors. This is for the reason that fatty acids which are not neutralized tend to oxidize during the subsequent steps of the soap making process. This'eifect is not present to any detrimental extent, however, when a sufiicient percentage of the caustic alkali solution is mixed with the soap stock at the beginning of the process, as will be more fully described hereafter.

In the usual process of manufacturing boiled soap, the boiling and settling require from two to three weeks time, and furthermore in order to effectively recover the glycerol content of the mass in the form of glycerine, three or four washes or grainings in the soap kettle are required. This means that large quantities of steam are required, applied to the kettle both through open coils and closed coils. Furthermore, the amount of water which must be used to properly wash the glycerine from the soap is large, being from two to three pounds per pound of fat saponified. All of this water has to be heated to boiling temperature and this again consumes heat and steam.

In accordance with the present process the length of time required is considerably reduced. The steam consumption is also greatly lessened.

In order that my invention may be more clearly understood attention is hereby directed to the accompanying drawing forming part of this application and illustrating diagrammatically the steps of my improved process and a form of mechanism by which the same ma be carried out.

In the pre erred form of my process the soap stock, such as a neutral vegetable oil, tallow, or other soap stock, is run into a preheating tank or tanks, such as the preheaters 1, 1 indicated in the drawing. In these preheaters the stock will be mixed with a percentage of caustic soda which is calculated in relation to the saponification value of the fatty acids in the stock used. The percentage of caustic soda employed is, as stated above, such that there may subsequentl be a complete separation of the glycerol om the fatty acid radical of the glyceride while at the same time the fatty acids are left in the condition of an emulsion with the sodium oxide carried in the caustic solution.

The percentage of sodium oxide to be added to the soap stock in tanks 1 will, of course, differ with different soap stocks. It may, however, be said that excellent results are obtained when approximately one-third of the amount required for the complete neutralization of the fatty acids is added at this time.

The material is preferably thoroughly mixed in tanks 1, mechanical stirrers being indicated at 2 in the drawings. It is also desirable to heat the product in tanks 1 to amoderate temperature such, for example, as 160 degrees F.

From the tanks 1 the solution is run, through pipe 3, into an emulsifier or emulsifiers such as those indicated at 4. Any emulsifying apparatus may be used of such a character that the caustic soda and oil or fat are put into a fine state of subdivision and an exceedingly intimate contact of the sodium oxide and the fat obtained.

From the emulsifying apparatus the product is caused to pass through pipes 5 into autoclaves 6, 6 in which the material is subjected to a pressure which may range from 20 to 110 pounds, depending upon the nature of the soap stock used. The heat to which the material is subjected will be the heatcorresponding to the steam pressure used. The saponification of the fat is completed in this process by hydrolysis, to form a fatty acid emulsion consisting of an incomplete soap, unsaponified fats, etc., as stated, all of the glycerol being split off from the glycerides. The emulsion so formed will be practically water-insoluble, because of the fact that a sufficient amount of the water-insoluble unneut-ralized fat is present, this fat covering globules or particles of water-soluble material in the emulsion so as to render the emulsion as a whole practically water-insoluble, as stated.

After autoclaving the product the glycerine water is recovered by settling. This may be accomplished in the autoclaves themselves or by blowing the material over into the soap kettles indicated at 7, 7 or other receivers.

After settling out and removal of the glycerine, suflicient caustic soda will be added to the fatty acid emulsion to complete the manufacture of the desired soap. If, for example, only one-third of the amount of caustic soda required for complete neutralization was inserted in the tanks 1, the

remaining two-thirds of the amount required for complete neutralization will now be added. This may be done in ordinary soap kettles, such as those indicated at 7, after which the material is boiled in the usual manner to free the same of impurities, and settled in the usual way.

By way of example, it may be stated that cocoanut oil has a koetstofler number of 258. It may readily be determined that 100 pounds of cocoanut oil would require, theoretically, 14.28 pounds of sodium oxide to completely neutralize th same. I find that one-third of this amount or 4.76 pounds of sodium oxide maybe mixed with 100 pounds of cocoanut oil in the mixing tanks 1, that is to say, the quantity of caustic soda equivalent to 4.76 pounds of sodium oxide may be added to the oil in tanks 1. The remainder of the caustic soda, or an amount equivalent to 9.52 pounds of sodium oxide will then be added in the kettles 7 Cotton seed oil has a koetstofi'er number of 190. Accordingly, 100 pounds of oil require 10.52 pounds of sodium oxide for complete neutralization. In accordance with my process, caustic soda equivalent to 3.50 pounds of sodium oxide may be added to 100 pounds of cotton seed oil in tanks 1 and the remainder of the caustic soda or an amount equivalent to 7.02 pounds of sodium oxide added in the kettles 7.

Similarly, tallow has a koetstofi'er number of 195 which means that 10.79 pounds of sodium oxide is required for complete neu tralization of 100 pounds of tallow. Accordingly, an amount of caustic soda equivalent to 3.60 pounds of sodium oxide may be added to 100'pounds of tallow in tanks 1 and the remainder or an amount of caustic soda equivalent to 7.19 pounds of sodium oxide added in kettles 7.

Th above are given merely by way of example and not by way of limitation of my process. lVhen fatty acids are completely combined with caustic soda, as in the usual boiled soap process, the soap which is formed dissolves in the glycerine liquor. When, however, an incomplete soap is formed in the form of an emulsion, as is described above, this emulsion is considerably lighter than the glycerine solution and alsois insoluble in water so that I may secure separation of the two by settling. If desired, a small percentage of common salt may be added to the autoclave charge to prevent the possibility of any dissolving of the mulsion material in the glycerine liquor. The amount of salt which would be so added, however, would be a. very small quantit such, for example, as from 2 to 4%, an very much less than that required in the ordinary process of graining soaps in the soap kettle.

In regard to the use of the autoclaves 6 it A will be noted that by my process saponification is carried out at a pressure which may Masses be very much less than that usually emor oil are first emulsified, and heat and pressure then applied to the emulsion whereby glycerol is split off from the glyceride. In such processes, however, the end in view was merely the decomposition of the glyceride, not the perfection of an improved process for completely manufacturing soap. Furthermore, the alkali was used in exceedingly small quantities such as percentages of less than 1%, the emulsion produced was less complete than that produced by an emulsifying apparatus such as that I propose to use, and the pressure employed was considerably greater than that which is required herein. I use a larger amount of alkali, for reasons previously stated.

It may be noted that in my process the length of time required to manufacture soap may be reduced to about one-third of the time previously required. 'That is to say, in place of turning over a kettle of soap every three weeks, as is the customary practice in manufacturing boiled soap, the same amount of fat stock may be saponified and settled in about one weeks time. This greatly decreases the amount of fat stock and therefore capital which a manufacturer must have tied up in materials under process.

The steam consumption required directly for soap manufacture is reduced about onehalf in comparison with the ordinary boiled soap process. The finished product is similar in every respect to that now produced by the boiled soap process. The equipment involved is mechanically simple and easy to operate; the kettles now installed in boiled soap manufacturing plants may be used for settling the soap as usual, the kettle capacity of the plant, however, being greatly increased so that the capacity of the plant, as a whole, may be increased by the installation of the process described herein.

It should be understood that my invention is not limited strictly to the details described herein but is as broad as is indicated by the accompanying claims.

I claim:

1. Aprocess for manufacturing soap comprising, treating soap stock with alkali insuiiicient in quantity to neutralize all of the fatty acid, and forming a substantially water-insoluble emulsion, including an incomplete soap and unneutralized fat, splitting the unneutralized fat, separating out the glycerine liquors, adding suflicient alkali to make up the previous deficiency and completing the manufacture of the soap.

2. A process for manufacturing soap, comprising, mixing soap stock with caustic alkali solution in a proportion less than suflicient to neutralize all of the fatty acid of the stock, emulsifying "and saponifyin the material, settling and removing glycero adding sufiicient caustic alkali solution to complete the neutralization of the fatty acid of the stock, boiling and settling.

3. A process for) manufacturing soap,

comprising, mixing soap stock with caustic alkali solution in a proportion less than sufiicient to neutralize all of the fatty acid of the stock,;emulsifying the material, subjecting the same to heat and pressure in an autoclave, separating out the glycerine liquors, adding suflicient caustic alkali solution to complete the neutralization of the fatty acid of the stock, and completing the manufacture of the soap.

4. A process of manufacturing soap, comprising, mixing soap stock with caustic alkali solution in a proportion considerably less than sufiicient to neutralize all of the fatty acid of the stock, but greater than ten per cent of the amount required for complete neutralization, emulsifying the material, applying heat and pressure toseparate glycerol therefrom, removing the glycerol, adding suflicient caustic alkali solution to complete the neutralization of the fatty acid, and completing the manufacture of the soap.

5. A process for manufacturing soap, comprising. mixing soap stock with caustic alkali solution in a proportion approximately one third the amount required to neutralize all of the fatty acid. emulsifying the material, subjecting it to heat and pressure, removing the glycerine liquors, adding caustic alkali solution sufficient to complete the neutralization of the fatty acid, and

completing the manufacture of the soap.

Signed at Chicago, in the county OfCOOk and State of Illinois, this 15th day of January, A. 1)., 1921.

' JOHN W. BOD it 

